A coroner today said it could never be proved whether Diana, Princess of Wales, was pregnant when she died.

On the second day of the inquest into the death of Diana and Dodi Fayed in a Paris car crash in 1997, the jury heard some of the most intimate details of her life ever to be revealed.

Jurors were also shown a long sequence of detailed CCTV footage of Diana and Fayed's final day in Paris, much of it never seen before.

The images, taken from security cameras at the city's Ritz hotel, show the couple at the hotel and Fayed leaving it to visit a jeweller.

The coroner, Lord Justice Scott Baker, pointed towards evidence suggesting that Diana was not pregnant, including allegations that she had been taking the contraceptive pill.

However, he said the matter was unlikely ever to be resolved unequivocally, even though it was relevant to the hearing in two ways.

"First, her pregnancy or suspected pregnancy is said to have provided the motive or part of the motive for killing Diana," he told the jury.

"Second, her body was embalmed by the French and it is said that the purpose of this was to conceal that she was pregnant."

He said no pregnancy test had been carried out on Diana at the hospital where she was taken that night because there appeared to be no reason to do so.

After her death, she was examined both externally and in a formal post mortem examination, where no evidence that she was pregnant was picked up.

On the opening day of the inquest, Lord Justice Baker had cast doubt on a photograph purporting to show Diana pregnant.

However, he added: "It is likely that pregnancy is a matter that cannot be proved one way or the other in scientific terms in this case.

"You will, of course, consider the scientific evidence, such as it is, but you will also hear evidence from several sources about what Diana had to say to her friends, and intimate details of her personal life."

He told jurors they would have to decide whether the decision to embalm Diana's body in Paris was illegal.

Fayed's father, Mohamed Fayed, claims the procedure was ordered by MI6 to conceal evidence that she was pregnant.

The court was told that authorisation to embalm a body in France was needed from both the local mayor and relatives of the deceased.

Authorisation on the official side came from the police because the crash happened early in the morning.

However, the final decision was taken by Diana's personal secretary, Michael Gibbins, and Colin Tebbutt, a former royal protection officer who was working as a security consultant for the princess, the jury heard.

"You will have to consider whether, as it is claimed, there was a breach of French law in embalming Diana's body and, if there was, whether this was more than technical failure to obtain the necessary approval," the coroner said.

"Mr Fayed claims the embalming was carried out on the specific instructions of the British authorities, namely MI6."

Lord Justice Baker said he hoped to call Diana's former butler Paul Burrell to give evidence in person and address many of the areas of dispute.

Diana and Fayed, along with their driver Henri Paul, died in a car crash in the French capital on August 31 1997.

The inquest will investigate allegations by Mohamed Fayed that the couple were murdered by MI6 under the orders of the Duke of Edinburgh because he believed Diana was pregnant and could have been about to remarry.

The Harrods owner claims Diana's calls were being listened to by the secret services, who would have heard her revealing that she was pregnant.

He is also convinced that blood and other samples taken from Paul's body, showing alcohol levels roughly twice the UK drink-drive limit, were switched to give a false reading.

The coroner said the jury would have to contend with questions over the contents and reliability of blood samples and other tests taken from Mr Paul.

"You may conclude that there are some unsatisfactory features about aspects of the sampling and recording procedures," he told the jury. "Some of the results are puzzling."

The coroner said there was differing evidence on whether Paul had been drunk. While samples indicated he was over the UK drink-drive limit, witnesses reported seeing no obvious sign of intoxication that night, he said.

"There is a major issue over whether or not he was unfit to drive through drink or drugs but also whether evidence has been fabricated or made up to suggest that he was drunk when, in truth, he was not," he added.

The former Metropolitan police commissioner Lord Stevens, who investigated the case in a three-year Scotland Yard inquiry, is expected to give evidence, the court heard.

He will have to explain why he told Paul's parents that their son was not drunk but, in the inquiry report, concluded that he was.

"I anticipate Lord Stevens will give evidence that he was trying to reassure the Pauls that their son had not been 'as drunk as a pig' as had been alleged in some newspapers," the coroner said.

Mr Fayed criticised the coroner on the opening day of the inquest. "The lawyers had been led to believe that it would be a very neutral outline of the case ahead," his spokesman, Michael Cole, said.

"But contentious and disputed matters were introduced at a very early stage - and that could have presented the appearance of bias, whether it was intended or not."